This invention relates to an arrangement for an oil/air breather outlet and in particular although not exclusively an oil/air breather outlet for a gas turbine engine.
During the normal operation of a gas turbine engine a bearing chamber of such an engine normally contains a lubricating oil. The bearing chamber is held under a negative pressure to ensure oil does not undesirably escape from the bearing chamber into the rest of the engine. To maintain a negative pressure therein, air is bled out of the bearing chamber, however, an amount of oil in the form of droplets or particles is also removed with the air. This liquid dispersion, a mixture of air and oil droplets, is then passed to an oil/air separator. The separated oil is returned to the lubrication system while the air is discharged overboard, through the breather assembly. However, not all the oil is removed from the air which is exhausted overboard. This oil/air mixture has the appearance of smoke or steam and which has been mistakenly assumed to be an engine fault.
It is the object of the present invention to provide apparatus to obviate the above problem.
According to the present invention there is provided a breather outlet for discharging a liquid dispersion therefrom comprising a outlet pipe wherein the breather outlet further comprises an electromagnetic wave generator so that, in use, electromagnetic waves produced by the wave generator impart sufficient electromagnetic energy to the liquid dispersion to evaporate at least a portion thereof.
Preferably the breather outlet comprises a wave-guide, wave-guide is so configured that, in use, it focuses the electromagnetic energy, produced by the wave generator, into the outlet pipe whereby the waves impart energy to the liquid dispersion.
Preferably the breather outlet comprises a containment device for containing the electromagnetic waves.
Preferably the electromagnetic wave generator generates electromagnetic energy selected from any one of the group comprising microwaves, ultrasonic waves, infrared radiation and gamma rays.
Preferably the liquid dispersion comprises oil and the liquid is in a particulate form.
Preferably a gas turbine engine comprises a breather outlet as described herein.
Preferably a method of operating a gas turbine engine, the engine comprising a breather outlet as set out in the preceding paragraphs, a weight-on-wheels signal and a power supply for providing power to a wave generator, the method comprising the steps of: enabling the power supply to the wave generator of the breather outlet at engine start-up; disabling the power supply when the weight-on-wheels signal switches off; enabling the power supply when the weight-on-wheels signal switches on. Furthermore it is preferred that the method comprises the step of disabling the power supply at engine shutdown.